Flash light



arch 22, 1927. 1,621,955

,1. A. SCHIFFNER FLASH LIGHT Filed Feb. 19, 1926 Patented 4 Mar. 22, 1927.

1 UNITED sm es PATENT OFFICE.

JOSEPH A. SCHIFFNER, 01? DENVER, COLORADO, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS, OF ONE-THIRD TO HARRY SHWARTZ AND ONE-SIXTH TO MARCELUS-.' WITHERWAX, BOTH OF DENVER, COLORADO.

FLASH LIGHT.

Application filed February 19, 1926. Serial No. 89,325.

This invention relates to improvements in flash lights and has reference more particularly to improvements in the means. for concentrating the rays of light so as to form a beam of great intensity and for varying the angle of dispersion so as to cover greater or less areas at a given distance.

For some time past there has been sold electric lamps that. are of small size and which derive their supply of current from one or more dry batteries that are concealed within the body portion of these lamps. Lamps of this type are not intended for continuous illumination but are designed more particularly to give intense flashes of light for short periods and are therefore referred to as, and generally termed flash lightsl The ordinary flash light of this type is provided at one end with a miniature incandescent electric lamp that is located in a conical reflector whose outer end is closed by a plane-convex lens. This arrangement gives a constant angle of dispersion and pro ects the light in the form of a conical beam whose angle cannot be altered. It often happens that the object to be illuminated 1s quite far away and that it will be only faintly illumlnated by the light thrown from a flash light of usual construction as these are made for illuminating bodies quite near-at hand.

The object of this invention, as intimated above, is to produce a flash light in which the angularity of the cone of projected light can be readily adjusted so that the best possible illumination of the object may be obtained regardless of the distance.

The above and other objects that may become apparent as the description proceeds are attained by means of a construction which will now be described in detail, reference for this purpose being had to the accompanying drawing in which the preferred embodiment has been illustrated and in which:

Fig. 1 is a side elevation of the improved lamp;

Fig. 2 is a longitudinaldiametrical section of the lamp; and

Fig. 3 is a diagram showing the path of the light.

The improved lamp to which this invention relates comprises a c lindrical tubular member 1 which is adapte to contain one or more dry cells 2 that furnish current for Figure 2. By

the lamp 3. As this invention relates merely to an improvement in the manner of securmg the lenses 4 and 5 to the end of the tubular member 1, I shall not describe the construction of the handle and switch in detail as these may be of any common and well-known construction, but shall limit the description to my improvements and those parts that cooperate therewith. Secured to the front end of the tubular member 1 is a threaded ferrule 6. A reflector 7 having an outwardly extending flange 6' is secured to the end of the ferrule 6 in any suitable manner. This reflector has a threaded extension 9 for the reception of the lamp 3. A holding member having a threaded cylindrical extension 10 is secured to the ferrule 6 and carries the lens 4: which is preferably secured to this member by having its edge 11 fitted into a groove that is formed by spinning the metal of the holder. The bolding member may be rotated about the ferrule so as to vary the distance between the optical center of the lens and the source of light, if this should be found desirable. The holding member has a conical portion 12 that extends outwardly from the part that is spun about the edge of the lens 4 and this conical portion terminates in a cylinder threaded portion 13 of considerable length. A reflector 14 of substantially conical shape is provided at its outer end with reversely bent spring tongues 15 that engage the inner surface of the threaded portion 13 and serves to hold this reflector in place with its inner end in contact with the outer surface of the lens 4. A second holding member which is provided with a threaded portion 16 adapted to engage with the threaded portion 13 has secured to its outer end the lens 5. This lens is preferably secured in place by means of the flange 17 that is spun about the edge of the lens in the manner shown in rotating the lens 5 and its holder on the threaded cylindrical part 13, the lens may be moved towards or away from the lens 4: so as to vary the distance between the optical centers of the two lenses.

In Figure 3, I have shown a diagram in which the source of light has been indicated by the letter L. The rays of light extend from the door along lines LA where they become incident with the surface of the lens t. In the drawing lenses '4; and 5 have been shown as plano-convex lenses but double convex lenses may be substituted for these if desired as it is merely necessm /y that the lenses employed shall be of the converging type. I therefore wish it to be understood that the shape of the lens is merely illustrative and is not to be considered as in any way limiting the invention to this specific type of lens. lVhen the rays of light pass through the converging lens 4, they are refracted and extended through the material of the lens in the direction of lines A'B. After passing into the air on the other side of the lens, they are refracted still more and emerge in the direction of lines B C. When the rays of light enter the lens 5 at C, they j are again refracted in the direction of lines C D and are projected from lens 5 along lines D E. v

If the lens 4 remains stationary with respect to the source of light. the lines B and C will make a constant angle with the principal optical axes L O of the two lenses which axes coincide and extend through the source of light in the manner shown in this figure. When lens 5 is moved away from lens 4 so as to increase the distance between the optical centers of the two lenses, the rays B and C will become incident with the rear surface of lens 5 at points F which, as indicated is nearer to the outer portion of the lens and the angle of the lens being greater at this point than near the center the light will be refracted to a larger extent in the manner indicated by dot anddash lines. In Fi ure 3, I have shown What may be considered the extreme case in which the beam of light emerges from the lens in the shape of a parallel cylinder. Ofcourse in the actual construction, there will be many rays of light that strike the surface of the reflector 7 and these may impinge on the lens 4 at different angles so that there will be stray rays of light emerging that do not conform to the arrangement shown in Figure 3, but as these.rays will be very small in number compared to the direct rays from the filament, they will not materially interfere with the action of the lam be noticed that the threaded sur ace 13 has purposely been made'of considerable length j and. that the threaded surface 15 that cooperates with it has also been shown as of substantially the same length. TlllS permits of an adjustment equal to the length of the tated on the ferrulefi so as to vary the distance of the lens 4 from the source of light, as above indicated, and this ad uStment can be used in connection with the adjustment of the lens 5 to procure the proper distribution of the light. The inner surface of It will the member 14 may be polished or have a glossy finish that will reflect the light and serves to direct stray rays of li ht onto the lens 5 so as to cause them to add to the brilliancy of the illumination. From the above it will appear that I haveproduced a lamp thatiis constructed substantially in the manner now employed in the manufacture of similar lamps, but which has the added advantage that the light can be focui'ed to a certain extent so as to enable the user to obtain the best possible illumination of any object, regardless of the distance at which he is from the object, as pointed out above. If a lamp has a fixed angle of dispersion, wood illumination can only be obtained when th lantern or lamp is held a fixed distance away from the object, but by means of the adjustability of the lens along their principal axes with respect to each other and with respect to the lamp, better results are obtained than can be obtained with a lamp having a fixed focus.

Having now described my; invention what I claim as new is: 7

1. A flash light comprisi ng, combination, a cylindrlcal casing adapted to contain a plurality'of dry cells,- a threaded ferrule secured to one end of'said casing, a reflector provided witha flange, said reflector extending into the casing and provided with a threaded opening adapted to receive a lamp, theflange of the reflector being secured to the outer end of the ferrule so as to be held from movement with respect thereto, a lens holding member having acylindrical threaded portion adapted to engage the threaded ferrule, and another threaded cylindrical portion of larger diameter, the two threaded portions being connected by a conical section, said holding member having a groove at the juncture of the smaller threaded section and the conical section, a lens in this groove whereby when the holding member is rotated the distance from the lamp to the optical center of the lens may be varied, a second lens holding member threadedly connected with the larger threaded portion and alens secured to the outer end of said second lens holding member whereby when it is rotated with respect to the first lens holding member the distance between the optical centers of the two lenses will be altered without altering the distance between the optical center of the first lens and the lamp.

2. A flash light comprising, in combination, acylindrical casing adapted to contain a plurality of dry cells. a threaded ferrule secured'toone end of said casing, a reflector provided with aflange, said reflector extending into the casing and provided with a threaded opening adapted to receive a cured to the outer end of the ferrule so as to "lamp, the flange of the reflector being se- 4 beheld from movement with respect thereto. a lens holding member having a c \'lindrieal threaded portion adapted to engage the threaded ferrule. and another threaded c lindrieal portion of larger diameter. the two threaded portions being connected by a conical section, said holding member having a groove at the juncture of the smaller threaded section and the conical section, a lens in this groove whereby when the holding member is rotated the distance from the lamp to the optical center of the lens may be varied, a second lens holding member threadedly connected with the larger threaded portion, a lens secured to the outer end of said sec- JOSEPH A. SCHIFFNER.

engage the in- 

